Biaxial tensile mechanical properties testing device and method for multi-configuration test pieces

Abstract

The present invention relates to a biaxial tensile mechanical property testing device and method for multi-configuration test pieces, which relate to the technical field of mechanical property testing of materials under complex stress loading, and specifically to a biaxial tensile mechanical property testing device and method for multi-configuration test pieces, including an upper clamp and a lower clamp connected to a testing machine and correspondingly arranged above and below, the upper clamp including an upper clamp body of an orthogonal cross configuration, the four protruding arms of the upper clamp body being upper support arms, the center lines of the four upper support arms being located in the same plane, an upper clamping portion for connecting to the testing machine being fixedly provided at the center of the upper clamp body, the upper clamping portion extending in a direction away from the lower clamp; the present invention has strong versatility, reduces the number of testing devices required for biaxial tensile mechanical property testing of test pieces with different configurations, and saves costs, that is, by adjusting the angle formed by the support rod and the base, the needs of biaxial tensile mechanical property testing of test pieces with different configurations and sizes can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical property testing of materials under complex stress loading, and in particular to a biaxial tensile mechanical property testing device and method for multi-configuration test pieces. Background Art

[0002] Currently, conventional quasi-static material testing machines and Hopkinson bars are commonly used to conduct uniaxial mechanical property tests on materials under various speed and temperature conditions. However, in actual engineering applications, structural components are often subjected to complex stress states, such as biaxial loading. Moreover, the mechanical properties of most materials are significantly affected by factors such as stress state and ambient temperature. Therefore, failure criteria and failure judgments established solely based on uniaxial mechanical property tests cannot truly and effectively assess the failure conditions or service life of most structural components in actual engineering applications.

[0003] Currently, large-scale quasi-static biaxial testing machines remain the primary device for conducting experimental research on the mechanical properties of materials under biaxial loading. However, these devices suffer from the following shortcomings: First, their maximum loading rate is typically less than 500 mm / min, which is insufficient for dynamic biaxial loading research. Second, these devices are typically not equipped with a suitable temperature chamber and temperature control device, and the cost of retrofitting them is high, meaning they cannot meet the requirements for studying the mechanical properties of materials under biaxial loading at different temperatures. Third, these devices are typically large and heavy, resulting in high construction, transportation, and maintenance costs. Consequently, these shortcomings severely limit their application in experimental research on the mechanical properties of materials under biaxial loading.

[0004] To study the mechanical properties of materials under biaxial loading, it is usually necessary to design an appropriate test specimen configuration based on the properties of the different materials and the loading characteristics of the testing machine or test device. This means that the configuration and dimensions of biaxially loaded test specimens for different materials vary significantly, and the connection method between the test specimen and the testing machine also varies. Furthermore, materials are more susceptible to deformation and failure under tensile loading than under compression. Therefore, it is urgent to develop a biaxial tensile mechanical properties testing apparatus and testing method that can accommodate multiple test specimen configurations. Summary of the Invention

[0005] The present invention aims to provide a biaxial tensile mechanical performance testing device and testing method suitable for multi-configuration test pieces, which is used to overcome the shortcomings of the background technology, improve the understanding of the mechanical properties of materials, and provide data support for further establishing failure criteria and failure judgment criteria, thereby evaluating the failure conditions or service life of corresponding structural parts.

[0006] The present invention provides a biaxial tensile mechanical property testing device for multi-configuration test pieces, comprising an upper fixture and a lower fixture connected to a testing machine and correspondingly arranged above and below, the upper fixture comprising an upper clamp body in an orthogonal cross configuration, the four protruding arms of the upper clamp body serving as upper support arms, the center lines of the four upper support arms being located in the same plane and having equal protruding lengths, an upper clamping portion for connecting to the testing machine being fixedly provided at the center of the upper clamp body, the upper clamping portion extending in a direction away from the lower fixture;

[0007] The lower fixture includes a cross-shaped base and a connecting piece. The four protruding arms of the base are lower support arms. The center lines of the four lower support arms are located in the same plane and have equal protruding lengths. A lower clamping portion for connecting to the testing machine is fixedly provided at the center of the base. The lower clamping portion extends in a direction away from the upper fixture.

[0008] The four protruding arms of the connecting member are connecting arms, the center lines of the four connecting arms are located in the same plane, and the protruding lengths are equal, and the protruding length of the lower support arm is greater than the protruding length of the upper support arm and the protruding length of the connecting arm;

[0009] The central axis of the upper clamp, the central axis of the base and the central axis of the connecting piece coincide with each other and are located on the same vertical line;

[0010] The extended ends of the four lower support arms on the base are correspondingly connected to the four connecting arms on the connecting member through a connecting device, and both ends of the connecting device are rotatably connected to a guide pulley;

[0011] The lower support arms are all slidably connected with test piece fixing devices, and a tensioning rope is connected to the side of the test piece fixing devices that are away from each other. The other end of the tensioning rope is fixedly connected to the corresponding upper support arm after passing through two guide pulleys on the corresponding connecting device.

[0012] Preferably, the connecting device comprises a support rod, both ends of which are fixedly connected to the corresponding connecting arm and the lower support arm respectively.

[0013] Preferably, the support rods include two support plates parallel to each other, the two guide pulleys located on the same support rod are arranged between the two support plates, and the guide pulleys are connected to the support plates through pins; the central axes of the guide pulleys are perpendicular to the planes of the support plates to which the guide pulleys are connected, and the central axes of the guide pulleys are parallel to the horizontal plane.

[0014] Preferably, it further includes an angle adjustment structure, the angle adjustment structure including a plurality of first connecting through holes arranged on the lower support arm along the axial direction of the lower support arm, a plurality of second connecting through holes uniformly distributed on the support rod along the axial direction of the support rod, and a plurality of third connecting through holes arranged on the connecting arm along the axial direction of the connecting arm;

[0015] The central axes of the first connecting through hole, the second connecting through hole and the third connecting through hole are all parallel to the horizontal plane;

[0016] One end of the support rod is fixedly connected via a connecting shaft passing through the first connecting through hole and the second connecting through hole, and the other end of the support rod is fixedly connected via another connecting shaft passing through another second through hole and the third connecting through hole;

[0017] The guide pulley is rotatably arranged on the support rod between the connection between the support rod and the connecting arm and the connection between the support rod and the lower support arm;

[0018] Adjust the connection position between the support rod and the connecting arm and the lower support arm to change the angle between the support rod and the base.

[0019] Preferably, the test piece fixing device includes a slider slidably arranged on the lower support arm, a connecting piece is provided on a surface of the slider facing the upper clamp, a pressing piece is pressed on the connecting piece, and the pressing piece is fixedly connected to the slider by a fourth screw passing through the connecting piece;

[0020] A first fixing hole is provided on each side of the sliders that are away from each other. An internal thread is provided in the first fixing hole. One end of the tensioning rope is provided in the first fixing hole and is fixedly connected to the first fixing hole by a first screw threadedly connected to the first fixing hole.

[0021] The tangent line of the circle of the guide pulley closer to the base among the two guide pulleys around which the tension rope connected to the first fixing hole is wound is on the same straight line as the central axis of the first fixing hole;

[0022] A snap-fit ​​groove is provided on the connecting piece, and the configuration size of the snap-fit ​​groove matches the clamping arm of the end of the test piece for connecting the clamp. The connecting arm of the test piece is provided in the snap-fit ​​groove, and the opening of the snap-fit ​​groove toward the center of the base is smaller than the opening of the snap-fit ​​groove away from the center of the base.

[0023] Preferably, a sliding through hole is provided on the slider, and the slider is sleeved on the connected lower support arm through the sliding through hole.

[0024] Preferably, a tensioning rope pre-tightening device is provided on each end of the upper support arm, and the tensioning rope pre-tightening device includes a pre-tightening hole provided on the end of the upper support arm and a second fixing hole provided on the end surface of the upper support arm, the central axis of the pre-tightening hole is parallel to the vertical line, the central axis of the second fixing hole is horizontally arranged, and the pre-tightening hole and the second fixing hole are perpendicular to each other and communicate with each other;

[0025] It also includes two support seats detachably connected to the ends of the upper support arms, the support seats are respectively arranged on both sides of the pre-tightening hole, the two support seats are connected by a pre-tightening rod, the pre-tightening rod and the support seats are both rotatably connected, a stopper is provided on one end of the pre-tightening rod, and at least two tensioning rope through holes are provided on the pre-tightening rod located between the two support seats;

[0026] The second fixing hole is provided with an internal thread, one end of the tensioning rope extends into the second fixing hole and is fixedly connected to the second fixing hole by a second screw threadedly connected to the second fixing hole;

[0027] When one end of the tensioning rope is extended into the second fixing hole, it comes out from the pre-tightening hole and passes through a tensioning rope through hole from bottom to top, and then passes through another tensioning rope through hole from top to bottom, and then it is carried out in sequence according to the length of the tensioning rope. Then the pre-tightening rod is rotated, and after the tensioning rope is pre-tightened, the second screw is turned, and the tensioning rope is fixedly connected to the second fixing hole.

[0028] Preferably, a connecting plate is provided on one end of the support seat connected to the upper support arm, a connecting socket is provided at a corresponding position on the upper support arm, the connecting plate is matched and connected to the connecting socket, and the support seat is detachably connected to the upper support arm through the matched connecting plate and connecting socket.

[0029] Alternatively, preferably, the upper clamping portion comprises an upper clamping block, one end of which is fixedly connected to a limiting plate;

[0030] A clamping block through hole is provided at the center of the upper clamping body, a limiting groove is provided at the center of a side of the upper clamping body facing the base, and the clamping block through hole is connected to the limiting groove;

[0031] The upper clamping block passes through the clamping block through hole, the limiting plate is matched and arranged in the limiting groove, and the limiting plate is fixedly connected to the upper clamping body by a third screw;

[0032] The lower clamping portion is a lower clamping block, which is fixedly connected to the center of the base and extends in a direction away from the upper clamp;

[0033] The central axes of the upper clamping block and the lower clamping block are both located on the same vertical line.

[0034] A method for testing the biaxial tensile mechanical properties of a multi-configuration test piece is provided, wherein the method is performed using a biaxial tensile mechanical properties testing device for a multi-configuration test piece.

[0035] When testing the mechanical properties of a test piece under wide-temperature quasi-static biaxial tensile loading, the method includes the following steps: step (1), equipping a quasi-static uniaxial testing machine with a temperature box and a temperature control device, and adjusting the position of the temperature box equipped with the quasi-static uniaxial testing machine so that the upper clamping end and the lower clamping end of the quasi-static uniaxial testing machine are located in the middle area of ​​the temperature box;

[0036] Step (2), connecting the upper clamping portion of the upper clamp and the lower clamping portion of the lower clamp to the upper clamping end and the lower clamping end of the quasi-static uniaxial testing machine respectively, so that the upper clamp and the lower clamp meet the coaxiality requirement in the vertical direction, and fixing them;

[0037] According to the configuration and size of the test piece, adjust the connection position of the support rod, the connecting arm and the lower support arm so that the angle formed by the support rod and the base meets the requirements. After adjustment, fix the connecting piece, the support rod and the base together through the pin;

[0038] Step (3), start the quasi-static uniaxial testing machine, with the lower clamping end of the quasi-static uniaxial testing machine fixed and the upper clamping end running vertically upward without load to a preset height, and check whether the connected test system runs smoothly during the loading process to avoid any jamming;

[0039] Step (4), when the connected test system runs smoothly, the quasi-static uniaxial testing machine and the biaxial tensile mechanical property testing device of a multi-configuration test piece are reset, and the data are cleared;

[0040] Step (5), respectively connect the four clamping arms on the test piece with the four test piece fixing devices slidably connected to the lower support arm, and then fix one end of the four tensioning ropes in the first fixing holes on the four test piece fixing devices and fix them by the first screws, and the other end of the tensioning ropes are respectively wound around the guide pulleys on the corresponding support rods, and then respectively pass through the corresponding second fixing holes and pre-tightening holes in turn, and then pass through the first tensioning rope through hole of the corresponding pre-tightening rod from bottom to top, and then pass through the second tensioning rope through hole from top to bottom, and proceed in sequence according to the length of the tensioning rope, rotate the pre-tightening rod, and the four pre-tightening rods are rotated the same number of times, so that the four tensioning ropes maintain a consistent pre-tightening force and are pre-tightened, and then fix the four pre-tightened tensioning ropes in the second fixing hole by the second screw that matches the size and thread of the second fixing hole, completing the entire pre-tightening work and tensioning rope fixed connection work;

[0041] After the pre-tightening is completed, the support seat and the pre-tightening rod are removed, and the tensioning rope is passed through the end away from the first fixing hole to separate it from the upper clamping body;

[0042] Step (6), setting the temperature in the temperature box and the loading rate of the quasi-static uniaxial testing machine according to the performance analysis requirements of the test piece;

[0043] Step (7) is to carry out a wide temperature quasi-static biaxial tensile mechanical property test under preset temperature conditions and loading rate conditions, and to stretch the test piece by driving the sliding device through the tension rope until the test piece is completely broken, and to record the load and displacement of the test piece during deformation, and convert them into corresponding stress-strain curves;

[0044] When testing the mechanical properties of a test piece under dynamic biaxial tensile loading, the method comprises the following steps:

[0045] Step (1) connects the upper clamping end and the lower clamping end of the new uniaxial high strain rate hydraulic servo testing machine to the upper clamping part of the upper fixture and the lower clamping part of the lower fixture, and after connection, makes the upper fixture and the lower fixture meet the coaxiality requirement in the vertical direction, and fixes them;

[0046] According to the configuration and size of the test piece, adjust the connection position of the support rod, the connecting arm and the lower support arm so that the angle formed by the support rod and the base meets the requirements. After adjustment, fix the connecting piece, the support rod and the base together through the pin;

[0047] Step (3) starts the new uniaxial high strain rate hydraulic servo testing machine, the lower clamping end of the new uniaxial high strain rate hydraulic servo testing machine is fixed, the upper clamping end slides vertically upward along the upper clamping part of the upper clamp, and completes pre-acceleration to the set loading rate within the length range of the upper clamping part, then clamps the upper clamping part and runs it to a preset height at the set loading rate without load, and checks whether the connected test system runs smoothly during the loading process to avoid jamming;

[0048] Step (4), when the connected test system runs smoothly, the new uniaxial high strain rate hydraulic servo testing machine and the biaxial tensile mechanical property testing device of a multi-configuration test piece are reset and the data are cleared;

[0049] Step (5), respectively connect the four clamping arms on the test piece with the four test piece fixing devices slidably connected to the lower support arm, and then fix one end of the four tensioning ropes in the first fixing holes on the four test piece fixing devices and fix them by the first screws, and the other end of the tensioning ropes are respectively wound around the guide pulleys on the corresponding support rods, and then respectively pass through the corresponding second fixing holes and pre-tightening holes in turn, and then pass through the first tensioning rope through hole of the corresponding pre-tightening rod from bottom to top, and then pass through the second tensioning rope through hole from top to bottom, and proceed in sequence according to the length of the tensioning rope, rotate the pre-tightening rod, and the four pre-tightening rods are rotated the same number of times, so that the four tensioning ropes maintain a consistent pre-tightening force and are pre-tightened, and then fix the four pre-tightened tensioning ropes in the second fixing hole by the second screw that matches the size and thread of the second fixing hole, completing the entire pre-tightening work and tensioning rope fixed connection work;

[0050] After the pre-tightening is completed, the support seat and the pre-tightening rod are removed, and the tensioning rope is passed through the end away from the first fixing hole to separate it from the upper clamping body;

[0051] Step (6), setting the loading rate of the new uniaxial high strain rate hydraulic servo testing machine according to the performance analysis requirements of the test piece;

[0052] Step (7) is to carry out a dynamic biaxial tensile mechanical property test under a preset loading rate condition, and to stretch the test piece by driving the sliding device through the tension rope until the test piece is completely broken, and to record the load and displacement of the test piece during deformation, and convert them into the corresponding stress-strain curve.

[0053] The beneficial effects of the present invention are as follows:

[0054] 1. The device of the present invention has high versatility, reducing the number of test devices required to adapt to biaxial tensile mechanical property tests of test pieces with different configurations, thereby saving costs. That is, by adjusting the angle formed by the support rod and the base, the requirements for biaxial tensile mechanical property tests of test pieces with different configurations and sizes can be met; by only adjusting the structural form of the connection parts such as the snap-fit ​​groove on the connecting piece of the test device and the shape and thickness of the pressing piece, the requirements for biaxial tensile mechanical property tests of test pieces of different thicknesses made of materials with different strengths and moduli can be met; and by only adjusting the length of the upper clamping part of the test device, it can be adapted to different types of material testing machines.

[0055] 2. The connection method between the device of the present invention and the test piece is relatively simple, and the connection time with the test piece is also short. There is no need to replace the components of the device after the test, which can meet the needs of large-scale repetitive tests. Secondly, the device of the present invention will not cause pre-damage to the test piece, thereby improving the reliability of the test results.

[0056] 3. The method proposed based on the testing device of the present invention overcomes the shortcomings of current research on the mechanical properties of materials under biaxial tension. The proposed method can not only meet the needs of experimental research on the mechanical properties of materials under wide-temperature quasi-static biaxial tension loading, further analyze the effects of temperature and loading rate on the mechanical properties of materials, and construct biaxial failure criteria and judgments that include the effects of temperature and loading rate, which can effectively evaluate the deformation and structural integrity of materials and structures under a wider range of temperature conditions; secondly, it can also meet the needs of experimental research on the mechanical properties of materials under dynamic biaxial tension loading such as impact, further analyze the effects of dynamic biaxial tension loads on the mechanical properties of materials, and construct biaxial failure criteria and judgments that consider the effects of dynamic loading, which can effectively evaluate the deformation and structural integrity of materials and structures under working conditions such as impact.

[0057] 4. The method proposed based on the testing device of the present invention is simple, convenient and highly reliable. It is easy to achieve the simultaneity of biaxial loading of the test piece during biaxial mechanical property testing, the stability of the rate during loading, and the observation of the deformation of the test piece. The test results are highly reliable.

[0058] 5. Compared with large-scale quasi-static biaxial testing machines sold on the market, the device of the present invention is relatively small in size and relatively light in weight, which makes it easy to carry and has low transportation costs. Secondly, the test system built based on the test device of the present invention has low construction and maintenance costs and good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0060] Figure 2 It is a schematic diagram of the overall structure of the upper clamp of the present invention.

[0061] Figure 3 It is a schematic diagram of the overall structure of the lower clamp of the present invention.

[0062] Figure 4 It is a schematic diagram of the specific structure of the upper clamp of the upper clamp of the present invention.

[0063] Figure 5 Schematic diagram of the upper clamping part structure of the upper clamp of the present invention.

[0064] Figure 6 This is a schematic structural diagram of the pre-tightening rod of the pre-tightening device of the upper clamp of the present invention.

[0065] Figure 7 This is a schematic structural diagram of the support base of the pre-tightening device of the upper clamp of the present invention.

[0066] Figure 8 This is a schematic diagram of the connection between the tensioning rope and the second fixing hole of the present invention.

[0067] Figure 9 This is a schematic diagram of the connecting piece structure of the lower clamp of the present invention.

[0068] Figure 10 This is a schematic diagram of the support rod structure of the lower clamp of the present invention.

[0069] Figure 11 This is a schematic diagram of the base structure of the lower clamp of the present invention.

[0070] Figure 12 It is a schematic diagram of the overall structure of the sliding device of the lower clamp of the present invention.

[0071] Figure 13 This is a schematic diagram of the slider structure of the sliding device of the lower clamp of the present invention.

[0072] Figure 14 The figure is a schematic diagram of a connecting piece structure of the sliding device of the lower clamp of the present invention.

[0073] Figure 15 This is a schematic diagram of the sheet pressing structure of the sliding device of the lower clamp of the present invention.

[0074] Figure 16 Schematic diagram of the connection between the connecting piece and the test piece of the present invention.

[0075] Figure markings: 1-support rod, 2-upper clamping body, 3-guide pulley, 4-base, 5-sliding device, 6-pre-tightening device, 7-upper clamping block, 8-second fixing hole, 9-pre-tightening hole, 10-pre-tightening rod, 11-connecting piece, 12-limiting groove, 13-limiting plate, 14-clamping block through hole, 16-third connecting through hole, 17-second connecting through hole, 18-first connecting through hole, 19-pressing plate, 20-connecting plate, 21-slider, 22-lower clamping block, 23-first fixing hole, 24-tensioning rope, 25-second screw, 26-clamping arm. DETAILED DESCRIPTION

[0076] The present invention provides a biaxial tensile mechanical property testing device for multi-configuration test pieces, comprising an upper fixture and a lower fixture connected to a testing machine and correspondingly arranged above and below, the upper fixture comprising an upper fixture body 2 in an orthogonal cross configuration, the four extending arms of the upper fixture body 2 serving as upper support arms, the center lines of the four upper support arms being located in the same plane and having equal extending lengths, an upper clamping portion for connecting to the testing machine being fixedly provided at the center of the upper fixture body 2, the upper clamping portion extending in a direction away from the lower fixture;

[0077] The lower fixture comprises a cross-shaped base 4 and a connector 11. The base 4 is larger than the entire upper fixture, facilitating operation and control while minimizing tension. The four protruding arms of the base 4 serve as lower support arms, their centerlines coplanar and extending to equal lengths. A lower clamping portion, designed for connection to the testing machine, is fixedly mounted at the center of the base 4. This lower clamping portion extends away from the upper fixture.

[0078] The four protruding arms of the connecting member 11 are connecting arms. The center lines of the four connecting arms are located in the same plane and have the same protruding lengths. The protruding length of the lower support arm is greater than the protruding length of the upper support arm and the protruding length of the connecting arm.

[0079] The central axis of the upper clamp body 2, the central axis of the base 4 and the central axis of the connecting member 11 coincide with each other and are located on the same vertical line;

[0080] The extended ends of the four lower support arms on the base 4 are correspondingly connected to the four connecting arms on the connecting member 11 through a connecting device, and the guide pulleys 3 are rotatably connected to both ends of the connecting device;

[0081] The lower support arms are all slidably connected with test piece fixing devices, and a tensioning rope 24 is connected to the side of the test piece fixing devices away from each other. The other end of the tensioning rope 24 is fixedly connected to the corresponding upper support arm after passing through the two guide pulleys 3 on the corresponding connecting device.

[0082] The connecting device includes a support rod 1, and both ends of the support rod 1 are fixedly connected to the corresponding connecting arm and the lower support arm respectively.

[0083] The support rods 1 include two support plates parallel to each other. The two guide pulleys 3 located on the same support rod 1 are arranged between the two support plates, and the guide pulleys 3 are connected to the support plates through pins; the central axes of the guide pulleys 3 are perpendicular to the planes of the support plates to which the guide pulleys 3 are connected, and the central axes of the guide pulleys 3 are parallel to the horizontal plane.

[0084] It also includes an angle adjustment structure, which includes a plurality of first connecting through holes 18 arranged on the lower support arm along the axial direction of the lower support arm, a plurality of second connecting through holes 17 uniformly distributed on the support rod 1 along the axial direction of the support rod 1, and a plurality of third connecting through holes 16 arranged on the connecting arm along the axial direction of the connecting arm;

[0085] The central axes of the first connecting through hole 18, the second connecting through hole 17 and the third connecting through hole 16 are all parallel to the horizontal plane;

[0086] One end of the support rod 1 is fixedly connected via a connecting shaft passing through the first connecting through-hole 18 and the second connecting through-hole 17, and the other end of the support rod 1 is fixedly connected via another connecting shaft passing through another second through-hole and the third connecting through-hole 16;

[0087] The guide pulley 3 is rotatably arranged on the support rod 1 between the connection between the support rod 1 and the connecting arm and the connection between the support rod 1 and the lower support arm;

[0088] Adjust the connection position between the support rod 1 and the connecting arm and the lower support arm to change the angle between the support rod 1 and the base 4.

[0089] The test piece fixing device includes a slider 21 slidably mounted on the lower support arm. A connecting piece 20 is provided on the side of the slider 21 facing the upper fixture. A pressing piece 19 is pressed onto the connecting piece 20. The pressing piece 19 is fixed to the slider 21 by a fourth screw passing through the connecting piece 20.

[0090] A first fixing hole 23 is provided on each side of the slider 21 that is away from each other. An internal thread is provided in the first fixing hole 23. One end of the tensioning rope 24 is provided in the first fixing hole 23 and is fixed to the first fixing hole 23 by a first screw threadedly connected to the first fixing hole 23.

[0091] The tangent line of the circle of the two guide pulleys 3 around which the tension rope 24 connected to the first fixing hole 23 is wound, the guide pulley 3 closer to the base 4, and the central axis of the first fixing hole 23 are on the same straight line;

[0092] A snap-fit ​​groove is provided on the connecting piece 20, and the configuration size of the snap-fit ​​groove matches the clamping arm 26 of the connecting fixture at the end of the test piece. The connecting arm of the test piece is set in the snap-fit ​​groove, and the opening of the snap-fit ​​groove toward the center of the base 4 is smaller than the opening of the snap-fit ​​groove away from the center of the base 4.

[0093] The slider 21 is provided with a sliding through hole, and the slider 21 is sleeved on the connected lower support arm through the sliding through hole. The slider 21 is made of a material with high rigidity and strength but low mass to reduce inertia, thereby improving the accuracy of the test results.

[0094] A tensioning rope pre-tightening device 6 is provided on each end of the upper support arm. The tensioning rope pre-tightening device 6 includes a pre-tightening hole 9 provided on the end of the upper support arm and a second fixing hole 8 provided on the end surface of the upper support arm. The central axis of the pre-tightening hole 9 is parallel to the vertical line, and the central axis of the second fixing hole 8 is horizontally arranged. The pre-tightening hole 9 and the second fixing hole 8 are perpendicular to each other and communicate with each other.

[0095] It also includes two support seats detachably connected to the ends of the upper support arms, the support seats are respectively arranged on both sides of the pre-tightening hole 9, and the two support seats are connected by a pre-tightening rod 10, the pre-tightening rod 10 and the support seats are both rotatably connected, a stopper is provided on one end of the pre-tightening rod 10, and at least two tensioning rope through holes are provided on the pre-tightening rod 10 located between the two support seats;

[0096] The second fixing hole 8 is provided with an internal thread, one end of the tensioning rope 24 extends into the second fixing hole 8 and is fixed to the second fixing hole 8 by a second screw 25 threadedly connected to the second fixing hole 8;

[0097] When one end of the tensioning rope 24 extends into the second fixing hole 8, it comes out from the pre-tightening hole 9 and passes through one tensioning rope through hole from bottom to top, and then passes through another tensioning rope through hole from top to bottom, it is carried out in sequence according to the length of the tensioning rope 24, and then the pre-tightening rod 10 is rotated. After the tensioning rope 24 is pre-tightened, the second screw 25 is rotated, and the tensioning rope 24 is fixedly connected to the second fixing hole 8.

[0098] A connecting plug plate is provided on one end of the support seat connected to the upper support arm, and a connecting socket is provided at a corresponding position on the upper support arm. The connecting plug plate is matched and connected to the connecting socket, and the support seat is detachably connected to the upper support arm through the matched connecting plug plate and connecting socket.

[0099] The upper clamping portion includes an upper clamping block 7, one end of which is fixedly connected to a limiting plate 13;

[0100] A clamping block through hole 14 is provided at the center of the upper clamping body 2, and a limiting groove 12 is provided at the center of one side of the upper clamping body 2 facing the base 4, and the clamping block through hole 14 is connected to the limiting groove 12;

[0101] The upper clamping block 7 passes through the clamping block through hole 14, the limiting plate 13 is matched and arranged in the limiting groove 12, and the limiting plate 13 is fixedly connected to the upper clamping body 2 by a third screw;

[0102] The lower clamping portion is a lower clamping block 22, which is fixedly connected to the center of the base 4 and extends in a direction away from the upper clamp;

[0103] The central axes of the upper clamping block 7 and the lower clamping block 22 are located on the same vertical line.

[0104] A method for testing the biaxial tensile mechanical properties of a multi-configuration test piece is provided, wherein the method is performed using a biaxial tensile mechanical properties testing device for a multi-configuration test piece.

[0105] When testing the mechanical properties of a test piece under wide-temperature quasi-static biaxial tensile loading, the method includes the following steps: step (1), equipping a quasi-static uniaxial testing machine with a temperature box and a temperature control device, and adjusting the position of the temperature box equipped with the quasi-static uniaxial testing machine so that the upper clamping end and the lower clamping end of the quasi-static uniaxial testing machine are located in the middle area of ​​the temperature box;

[0106] Step (2), connecting the upper clamping portion of the upper clamp and the lower clamping portion of the lower clamp to the upper clamping end and the lower clamping end of the quasi-static uniaxial testing machine respectively, so that the upper clamp and the lower clamp meet the coaxiality requirement in the vertical direction, and fixing them;

[0107] According to the configuration and size of the test piece, adjust the connection position of the support rod 1 with the connecting arm and the lower support arm so that the angle formed by the support rod 1 and the base 4 meets the requirements. After adjustment, fix the connecting piece 11, the support rod 1 and the base 4 together through the pin;

[0108] Step (3), start the quasi-static uniaxial testing machine, with the lower clamping end of the quasi-static uniaxial testing machine fixed and the upper clamping end running vertically upward without load to a preset height, and check whether the connected test system runs smoothly during the loading process to avoid any jamming;

[0109] Step (4), when the connected test system runs smoothly, the quasi-static uniaxial testing machine and the biaxial tensile mechanical property testing device of a multi-configuration test piece are reset, and the data are cleared;

[0110] Step (5), respectively connect the four clamping arms 26 on the test piece with the four test piece fixing devices slidably connected on the lower support arm, and then fix one end of the four tensioning ropes 24 in the first fixing holes 23 on the four test piece fixing devices and fix them by the first screw, and the other end of the tensioning rope 24 is respectively wound around the guide pulley 3 on the corresponding support rod 1, and then respectively pass through the corresponding second fixing hole 8 and pre-tightening hole 9 in turn, and then pass through the first tensioning rope through hole of the corresponding pre-tightening rod 10 from bottom to top, and then pass through the second tensioning rope through hole from top to bottom, and proceed in sequence according to the length of the tensioning rope 24, rotate the pre-tightening rod 10, and the number of rotations of the four pre-tightening rods 10 is the same, so that the four tensioning ropes 24 maintain a consistent pre-tightening force and are pre-tightened, and then fix the four pre-tightened tensioning ropes 24 in the second fixing hole 8 by the second screw 25 that matches the size and thread of the second fixing hole 8, completing the entire pre-tightening work and the tensioning rope 24 fixed connection work;

[0111] After the pre-tightening is completed, the support base and the pre-tightening rod 10 are removed, and the tensioning rope 24 is passed through the end away from the first fixing hole 23 to separate it from the upper clamp body 2;

[0112] Step (6), setting the temperature in the temperature box and the loading rate of the quasi-static uniaxial testing machine according to the performance analysis requirements of the test piece;

[0113] Step (7) is to carry out a wide temperature quasi-static biaxial tensile mechanical property test under preset temperature conditions and loading rate conditions, and the sliding device 5 is driven by the tension rope 24 to stretch the test piece until the test piece is completely broken, and the load and displacement of the test piece during deformation are recorded and converted into the corresponding stress-strain curve;

[0114] When testing the mechanical properties of a test piece under dynamic biaxial tensile loading, the method comprises the following steps:

[0115] Step (1) connects the upper clamping end and the lower clamping end of the new uniaxial high strain rate hydraulic servo testing machine to the upper clamping part of the upper fixture and the lower clamping part of the lower fixture, and after connection, makes the upper fixture and the lower fixture meet the coaxiality requirement in the vertical direction, and fixes them;

[0116] According to the configuration and size of the test piece, adjust the connection position of the support rod 1 with the connecting arm and the lower support arm so that the angle formed by the support rod 1 and the base 4 meets the requirements. After adjustment, fix the connecting piece 11, the support rod 1 and the base 4 together through the pin;

[0117] Step (3) starts the new uniaxial high strain rate hydraulic servo testing machine, the lower clamping end of the new uniaxial high strain rate hydraulic servo testing machine is fixed, the upper clamping end slides vertically upward along the upper clamping part of the upper clamp, and completes pre-acceleration to the set loading rate within the length range of the upper clamping part, then clamps the upper clamping part and runs it to a preset height at the set loading rate without load, and checks whether the connected test system runs smoothly during the loading process to avoid jamming;

[0118] Step (4), when the connected test system runs smoothly, the new uniaxial high strain rate hydraulic servo testing machine and the biaxial tensile mechanical property testing device of a multi-configuration test piece are reset and the data are cleared;

[0119] Step (5), respectively connect the four clamping arms 26 on the test piece with the four test piece fixing devices slidably connected on the lower support arm, and then fix one end of the four tensioning ropes 24 in the first fixing holes 23 on the four test piece fixing devices and fix them by the first screw, and the other end of the tensioning rope 24 is respectively wound around the guide pulley 3 on the corresponding support rod 1, and then respectively pass through the corresponding second fixing hole 8 and pre-tightening hole 9 in turn, and then pass through the first tensioning rope through hole of the corresponding pre-tightening rod 10 from bottom to top, and then pass through the second tensioning rope through hole from top to bottom, and proceed in sequence according to the length of the tensioning rope 24, rotate the pre-tightening rod 10, and the number of rotations of the four pre-tightening rods 10 is the same, so that the four tensioning ropes 24 maintain a consistent pre-tightening force and are pre-tightened, and then fix the four pre-tightened tensioning ropes 24 in the second fixing hole 8 by the second screw 25 that matches the size and thread of the second fixing hole 8, completing the entire pre-tightening work and the tensioning rope 24 fixed connection work;

[0120] After the pre-tightening is completed, the support base and the pre-tightening rod 10 are removed, and the tensioning rope 24 is passed through the end away from the first fixing hole 23 to separate it from the upper clamp body 2;

[0121] Step (6), setting the loading rate of the new uniaxial high strain rate hydraulic servo testing machine according to the performance analysis requirements of the test piece;

[0122] Step (7) is to carry out a dynamic biaxial tensile mechanical property test under a preset loading rate condition, and to stretch the test piece by driving the sliding device 5 through the tension rope 24 until the test piece is completely broken, and to record the load and displacement of the test piece during deformation, and convert them into the corresponding stress-strain curve.

[0123] When testing using the above method, the thickness of the connecting piece 20 and the size of the engaging groove are adjusted according to the strength, modulus and size of the test piece material, and the number of the pressing pieces 19 is increased or decreased accordingly, or the thickness of the pressing piece 19 is adjusted.

Claims

1. A biaxial tensile mechanical property testing device for multi-configuration test pieces, comprising an upper fixture and a lower fixture connected to a testing machine and correspondingly arranged above and below, characterized in that: The upper clamp comprises an upper clamp body (2) in an orthogonal cross configuration, the four protruding arms of the upper clamp body (2) being upper support arms, the center lines of the four upper support arms being located in the same plane, and the protruding lengths being equal, an upper clamping portion for connecting to the testing machine being fixedly provided at the center of the upper clamp body (2), and the upper clamping portion being extended in a direction away from the lower clamp; The lower fixture comprises a cross-shaped base (4) and a connecting member (11), the four protruding arms of the base (4) being lower support arms, the center lines of the four lower support arms being located in the same plane and having the same protruding lengths, a lower clamping portion for connecting to the testing machine being fixedly provided at the center of the base (4), the lower clamping portion being extended in a direction away from the upper fixture; The four protruding arms of the connecting member (11) are connecting arms, the center lines of the four connecting arms are located in the same plane, and the protruding lengths are equal, and the protruding length of the lower support arm is greater than the protruding length of the upper support arm and the protruding length of the connecting arm; The central axis of the upper clamp body (2), the central axis of the base (4) and the central axis of the connecting member (11) coincide with each other and are located on the same vertical line; The extended ends of the four lower support arms on the base (4) are correspondingly connected to the four connecting arms on the connecting member (11) through a connecting device, and guide pulleys (3) are rotatably connected to both ends of the connecting device; The lower support arms are all slidably connected to test piece fixing devices, and a tensioning rope (24) is connected to the side of the test piece fixing devices that is away from each other, and the other end of the tensioning rope (24) is wound around two guide pulleys (3) on the corresponding connecting device and then fixedly connected to the corresponding upper support arm; The connecting device comprises a support rod (1), wherein both ends of the support rod (1) are fixedly connected to corresponding connecting arms and lower support arms respectively; Each support rod (1) includes two support plates parallel to each other, and two guide pulleys (3) located on the same support rod (1) are arranged between the two support plates, and the guide pulleys (3) are connected to the support plates via pins; the central axes of the guide pulleys (3) are perpendicular to the plane of the support plates to which the guide pulleys (3) are connected, and the central axes of the guide pulleys (3) are parallel to the horizontal plane; It also includes an angle adjustment structure, the angle adjustment structure including a plurality of first connecting through holes (18) arranged on the lower support arm along the axial direction of the lower support arm, a plurality of second connecting through holes (17) uniformly distributed on the support rod (1) along the axial direction of the support rod (1), and a plurality of third connecting through holes (16) arranged on the connecting arm along the axial direction of the connecting arm; The central axes of the first connecting through hole (18), the second connecting through hole (17) and the third connecting through hole (16) are all parallel to the horizontal plane; One end of the support rod (1) is fixedly connected via a connecting shaft passing through the first connecting through hole (18) and the second connecting through hole (17), and the other end of the support rod (1) is fixedly connected via another connecting shaft passing through another second through hole and the third connecting through hole (16); The guide pulley (3) is rotatably arranged on the support rod (1) between the connection point between the support rod (1) and the connecting arm and the connection point between the support rod (1) and the lower support arm; Adjust the connection position between the support rod (1) and the connecting arm and the lower support arm to change the angle between the support rod (1) and the base (4).

2. A biaxial tensile mechanical properties testing device for a multi-configuration test piece according to claim 1, characterized in that: The test piece fixing device comprises a slider (21) slidably arranged on the lower support arm, a connecting piece (20) is provided on a surface of the slider (21) facing the upper clamp, a pressing piece (19) is pressed onto the connecting piece (20), and the pressing piece (19) is fixedly connected to the slider (21) by a fourth screw passing through the connecting piece (20); A first fixing hole (23) is provided on each side of the slider (21) that is away from each other. An internal thread is provided in the first fixing hole (23). One end of the tensioning rope (24) is provided in the first fixing hole (23) and is fixedly connected to the first fixing hole (23) via a first screw threadedly connected to the first fixing hole (23). The tangent line of the circle of the guide pulley (3) close to the base (4) among the two guide pulleys (3) around which the tension rope (24) connected to the first fixing hole (23) is wound is located on the same straight line as the central axis of the first fixing hole (23); The connecting piece (20) is provided with a snap-fit ​​groove, the configuration size of which matches the clamping arm (26) of the end of the test piece for connecting the clamp, the connecting arm of the test piece is arranged in the snap-fit ​​groove, and the opening of the snap-fit ​​groove toward the center of the base (4) is smaller than the opening of the snap-fit ​​groove away from the center of the base (4).

3. A biaxial tensile mechanical properties testing device for a multi-configuration test piece as claimed in claim 2, characterized in that: The slider (21) is provided with a sliding through hole, and the slider (21) is sleeved on the connected lower support arm through the sliding through hole.

4. The biaxial tensile mechanical properties testing device for a multi-configuration test piece according to claim 1, characterized in that: The ends of the upper support arms are provided with tension rope pre-tightening devices (6), the tension rope pre-tightening devices (6) comprising a pre-tightening hole (9) provided on the ends of the upper support arms and a second fixing hole (8) provided on the end surface of the upper support arms, the central axis of the pre-tightening hole (9) is parallel to the vertical line, the central axis of the second fixing hole (8) is provided horizontally, and the pre-tightening hole (9) and the second fixing hole (8) are perpendicular to each other and communicate with each other; It also includes two support seats detachably connected to the ends of the upper support arms, the support seats are respectively arranged on both sides of the pre-tightening hole (9), the two support seats are connected via a pre-tightening rod (10), the pre-tightening rod (10) and the support seats are both rotatably connected, a stopper is provided on one end of the pre-tightening rod (10), and at least two tensioning rope through holes are provided on the pre-tightening rod (10) located between the two support seats; An internal thread is provided in the second fixing hole (8), one end of the tensioning rope (24) extends into the second fixing hole (8), and is fixedly connected to the second fixing hole (8) via a second screw (25) threadedly connected to the second fixing hole (8); When one end of the tensioning rope (24) extends into the second fixing hole (8), it passes through the pre-tightening hole (9) and passes through one tensioning rope through hole from bottom to top and then passes through another tensioning rope through hole from top to bottom, and the process is carried out in sequence according to the length of the tensioning rope (24). Then, the pre-tightening rod (10) is rotated, and after the tensioning rope (24) is pre-tightened, the second screw (25) is rotated, and the tensioning rope (24) is fixedly connected to the second fixing hole (8).

5. The biaxial tensile mechanical properties testing device for multi-configuration test pieces according to claim 4, characterized in that: A connecting plug plate is provided on one end of the support base connected to the upper support arm, and a connecting socket is provided at a corresponding position on the upper support arm. The connecting plug plate and the connecting socket are matched and connected, and the support base is detachably connected to the upper support arm through the matched connecting plug plate and the connecting socket.

6. A biaxial tensile mechanical properties testing device for a multi-configuration test piece according to any one of claims 1 to 4, characterized in that: The upper clamping portion comprises an upper clamping block (7), one end of the upper clamping block (7) being fixedly connected to a limiting plate (13); A clamping block through hole (14) is provided at the center of the upper clamping body (2), a limiting groove (12) is provided at the center of a side of the upper clamping body (2) facing the base (4), and the clamping block through hole (14) is connected to the limiting groove (12); The upper clamping block (7) passes through the clamping block through hole (14), the limiting plate (13) is matched and arranged in the limiting groove (12), and the limiting plate (13) is fixedly connected to the upper clamping body (2) by a third screw; The lower clamping portion is a lower clamping block (22), which is fixedly connected to the center of the base (4), and the lower clamping block (22) extends in a direction away from the upper clamp; The central axes of the upper clamping block (7) and the lower clamping block (22) are both located on the same vertical line.

7. A method for testing the biaxial tensile mechanical properties of a multi-configuration test piece, the method being performed using the biaxial tensile mechanical properties testing device for a multi-configuration test piece as claimed in claim 1 or 4, characterized in that: When testing the mechanical properties of a test piece under wide-temperature quasi-static biaxial tensile loading, the method includes the following steps: step (1), equipping a quasi-static uniaxial testing machine with a temperature box and a temperature control device, and adjusting the position of the temperature box equipped with the quasi-static uniaxial testing machine so that the upper clamping end and the lower clamping end of the quasi-static uniaxial testing machine are located in the middle area of ​​the temperature box; Step (2), connecting the upper clamping portion of the upper clamp and the lower clamping portion of the lower clamp to the upper clamping end and the lower clamping end of the quasi-static uniaxial testing machine respectively, so that the upper clamp and the lower clamp meet the coaxiality requirement in the vertical direction, and fixing them; According to the configuration size of the test piece, the connection position of the support rod (1) and the connecting arm and the lower support arm is adjusted so that the angle formed by the support rod (1) and the base (4) meets the requirements, and after the adjustment, the connecting piece (11), the support rod (1) and the base (4) are fixedly connected by a pin; Step (3), start the quasi-static uniaxial testing machine, with the lower clamping end of the quasi-static uniaxial testing machine fixed and the upper clamping end running vertically upward without load to a preset height, and check whether the connected test system runs smoothly during the loading process to avoid any jamming; Step (4), when the connected test system runs smoothly, the quasi-static uniaxial testing machine and the biaxial tensile mechanical property testing device of a multi-configuration test piece are reset, and the data are cleared; Step (5), respectively connect the four clamping arms (26) on the test piece to the four test piece fixtures slidably connected on the lower support arm, then fix one end of the four tension ropes (24) in the first fixing holes (23) on the four test piece fixtures and fix them by the first screw, and the other end of the tension ropes (24) is respectively wound around the guide pulleys (3) on the corresponding support rods (1), and then respectively pass through the corresponding second fixing holes (8), pre-tightening holes (9) and pass through the corresponding pre-tightening rods (10) from bottom to top. ) through the first tensioning rope through hole from top to bottom, and then through the second tensioning rope through hole from top to bottom, and then rotate the pre-tightening rod (10) in sequence according to the length of the tensioning rope (24), and the four pre-tightening rods (10) rotate the same number of turns, so that the four tensioning ropes (24) maintain a consistent pre-tightening force and are pre-tightened, and then fix the four pre-tightened tensioning ropes (24) in the second fixing hole (8) by a second screw (25) that matches the size and thread of the second fixing hole (8), completing the entire pre-tightening work and the tensioning rope (24) fixed connection work; After the pre-tightening is completed, the support seat and the pre-tightening rod (10) are removed, and the tensioning rope (24) is passed through the end away from the first fixing hole (23) to separate it from the upper clamping body (2); Step (6), setting the temperature in the temperature box and the loading rate of the quasi-static uniaxial testing machine according to the performance analysis requirements of the test piece; Step (7) is to carry out a wide temperature quasi-static biaxial tensile mechanical property test under preset temperature conditions and loading rate conditions, and to stretch the test piece by driving the sliding device (5) through the tension rope (24) until the test piece is completely broken, and to record the load and displacement of the test piece during deformation, and convert them into corresponding stress-strain curves; When testing the mechanical properties of a test piece under dynamic biaxial tensile loading, the method comprises the following steps: Step (1) connects the upper clamping end and the lower clamping end of the new uniaxial high strain rate hydraulic servo testing machine to the upper clamping part of the upper fixture and the lower clamping part of the lower fixture, and after connection, makes the upper fixture and the lower fixture meet the coaxiality requirement in the vertical direction, and fixes them; According to the configuration size of the test piece, the connection position of the support rod (1) and the connecting arm and the lower support arm is adjusted so that the angle formed by the support rod (1) and the base (4) meets the requirements, and after the adjustment, the connecting piece (11), the support rod (1) and the base (4) are fixedly connected by a pin; Step (3) starts the new uniaxial high strain rate hydraulic servo testing machine, the lower clamping end of the new uniaxial high strain rate hydraulic servo testing machine is fixed, the upper clamping end slides vertically upward along the upper clamping part of the upper clamp, and completes pre-acceleration to the set loading rate within the length range of the upper clamping part, then clamps the upper clamping part and runs it to a preset height at the set loading rate without load, and checks whether the connected test system runs smoothly during the loading process to avoid jamming; Step (4), when the connected test system runs smoothly, the new uniaxial high strain rate hydraulic servo testing machine and the biaxial tensile mechanical property testing device of a multi-configuration test piece are reset and the data are cleared; Step (5), respectively connect the four clamping arms (26) on the test piece to the four test piece fixtures slidably connected on the lower support arm, then fix one end of the four tension ropes (24) in the first fixing holes (23) on the four test piece fixtures and fix them by the first screw, and the other end of the tension ropes (24) is respectively wound around the guide pulleys (3) on the corresponding support rods (1), and then respectively pass through the corresponding second fixing holes (8), pre-tightening holes (9) and pass through the corresponding pre-tightening rods (10) from bottom to top. ) through the first tensioning rope through hole from top to bottom, and then through the second tensioning rope through hole from top to bottom, and then rotate the pre-tightening rod (10) in sequence according to the length of the tensioning rope (24), and the four pre-tightening rods (10) rotate the same number of turns, so that the four tensioning ropes (24) maintain a consistent pre-tightening force and are pre-tightened, and then fix the four pre-tightened tensioning ropes (24) in the second fixing hole (8) by a second screw (25) that matches the size and thread of the second fixing hole (8), completing the entire pre-tightening work and the tensioning rope (24) fixed connection work; After the pre-tightening is completed, the support seat and the pre-tightening rod (10) are removed, and the tensioning rope (24) is passed through the end away from the first fixing hole (23) to separate it from the upper clamping body (2); Step (6), setting the loading rate of the new uniaxial high strain rate hydraulic servo testing machine according to the performance analysis requirements of the test piece; Step (7) is to carry out a dynamic biaxial tensile mechanical property test under a preset loading rate condition, and the sliding device (5) is driven by the tension rope (24) to stretch the test piece until the test piece is completely broken, and the load and displacement of the test piece during deformation are recorded and converted into a corresponding stress-strain curve.

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